1. Field of the Invention
The invention mainly relates to a novel microorganism strain Lactobacillus paracasei GM-080 and its use for stimulating IFN-γ secretion and treating allergy related diseases.
2. Description of the Related Art
Allergy refers to an acquired potential to develop immunologically mediated adverse reaction to normally innocuous substances. Allergic reaction provokes symptoms such as itching, coughing, wheezing, sneezing, watery eyes, inflammation and fatigue. It is normally believed that allergic reaction includes an early specific immune response and a late inflammatory reaction. It is reported that allergens (e.g., pollens and mite dust) mediate the early phase of allergy by stimulating high affinity immunoglobulin (IgE) receptors. For instance, mast cells and basophils, when stimulated by allergens, will release histamine and cytokines. The cytokines released from mast cells and basophils then mediate the late phase of allergy by recruiting inflammatory cells. It is also reported that the influx of eosinophils, macrophages, lymphocytes, neutrophils and platelets starts the vicious inflammatory cycle. This late phase of allergy amplifies the initial immune response, which in turn triggers the release of more inflammatory cells (Blease et al. Chemokines and their role in airway hyper-reactivity. Respir Res 2000; 1:54–61).
Various therapies have been pursued in order to treat the symptoms of allergies. Among them, anti-allergics and histamine H-receptor antagonists (anti-histamines) have been used. Histamine antagonists are administered to antagonize the action of histamine released from mast cells in response to the presence of allergens. They reduce the redness, itching and swelling caused by the action of histamine on the target tissues, and serve to prevent or alleviate many of the symptoms resulting from degranulation of mast cells. However, anti-histamines have also been associated with adverse reactions such as diminished alertness, slowed reaction times and somnolence (U.S. Patent No. 6,225,332).
There are also some reports on the treatment of allergies by regulating cytokines. Among them, interferon-γ (IFN-γ) was found to inhibit the over-expression of cytokines in Th2 lymphocytes, especially the secretion of IL-4 to lower the proliferation of B cells. Also, IFN-γ could stimulate the immune response of Th1 and repress the synthesis of IgE (Sareneva T et al. Influenza A virus-induced IFN-α/β and IL-18 synergistically enhance IFN-γ gene expression in human T cells. J Immunol 1998; 160:6032–6038; Shida K et al. Lactobacillus casei inhibits antigen-induced IgE secretion through regulation of cytokine production in murine splenocyte cultures. Int Arch Allergy Immunol 1998; 115:278–287). Since IFN-γ can repress B cell proliferation and IgE secretion, it is believed that IFN-γ is effective in treating allergy.
Lactic acid bacteria, which are gram-positive bacteria, are commonly used in industrial food fermentations. In recent studies, lactic acid bacteria were shown to stimulate IFN-γ secretion of cells (Contractor NV et al. Lymphoid hyperplasia, autoimmunity and compromised intestinal intraepithelial lymphocyte development in colitis-free gnotobiotic IL-2-deficient mice. J Immunol 1998; 160:385–394). Some specific lactic acid bacteria, such as Bifidobacterium lactis and Lactobacillus brevis subsp., were found to stimulate IFN-γ secretion of lymphocytes in blood derived from mice and humans (U.S. Patent Publication No. U.S. 2002/0031503 A1; U.S. Patent. No. 5,556,785). It was also reported that lactic acid bacteria could stimulate lymphocytes derived from humans or mice to secrete Interleukin-12 (IL-12), which was a T cell stimulatory cytokine activating T cells and NK cells to secrete IFN-γ (Hessle et al. Lactobacilli from human gastrointestinal mucosa are strong stimulators of IL-12 production. Clin Exp Immunol 1999; 116:276–282).
Lactobacillus paracasei has been used for manufacturing Cheddar and Italian ewe cheeses for a long time. It was found to grow and sustain high viability in cheese during ripening (Gardiner, G., Ross, R. P., Collins, J. K., Fitzgerald, G., Stanton, C. Development of a probiotic cheddar cheese containing human-derived Lactobacillus paracasei strains. Appl Environ Microbiol. 1998; 64: 2192–2199; Angelis, M., Corsetti, A., Tosti, N., Rossi, J., Corbo, M. R., Gobbetti, M. Characterization of non-starter lactic acid bacteria from Italian ewe cheeses based on phenotypic, genotypic, and cell wall protein analyses. Appl Environ Microbiol. 2001; 67: 2011–2020). L. paracasei was noticed to produce anti-bacteria and anti-yeast compounds such as H2O2 and proteinaceous active substance in human vagina and oral cavity (Atanassova, M., Choiset, Y., Dalgalarrondo, M., Chobert, J.-M., Dousset, X., Ivanova, I., Haertké, T. Isolation and partial biochemical characterization of a proteinaceous anti-bacteria and anti-yeast compound produced by Lactobacillus paracasei subsp. paracasei strain M3. Int. J. Food Microibiol. 2003; 87: 63–73; Ocaña, V. S., Holgado, A. A. P. de R., Nader-Macias, M. E. Growth inhibition of Staphylococcus aureus by H2O2-producing Lactobacillus paracasei subsp. paracasei isolated from the human vagina. FEMS Immunol. Med. Microbiol. 1999; 23: 87–92; Sookkhee S., Chulasiri, M., Prachyabrued, W. Lactic acid bacterial form healthy oral cavity of Thai volunteers: inhibition of oral pathogens. Journal of Applied Microbiology 2001; 90:172–179).